Speaker
Description
The study of late time correlation functions on top of a de Sitter
background is of prime interest in primordial cosmology.
Due to the non-conservation of energy, their evaluation represent a
significant technical challenge and their mathematical structure remains
unclear. In this talk, I will propose a new
direction to address both of these issues by introducing a
frequency-momentum space representation arising from the decomposition into
unitary irreducible representations of the space-time isometry group
SO(1,d+1), which trades the familiar (d+1)-dimensional Fourier space for
the Kontorovich-Lebedev-Fourier (KLF) space. At the non-perturbative
level, I will show that the de Sitter Kallen-Lehman representation directly
follows from the decomposition of the two-point function into KLF modes.
At the perturbative level, I will present how this formalism get rids
of the nested time integrals and allows us to simply evaluate some simple
loop diagrams.
| Other topic / keywords: | QFT in curved space-time, harmonic analysis, conformal field theory, group theory, symmetries |
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